package com.jinbei.common.util;

import com.jinbei.common.contants.Contants;

import java.awt.*;
import java.awt.image.BufferedImage;
import java.util.Random;

/**
 * @author zflu
 * 系统登录验证码生成器
 * 2018年7月9日10:40:08
 */
public class CaptchaUtil {

    private BufferedImage image;
    private String str;

    private CaptchaUtil() {
        init();
    }

    public static CaptchaUtil Instance() {
        return new CaptchaUtil();
    }

    /**
     * @Author zflu
     * @Description 获得验证码图片
     * @Date 2018/7/8 14:27
     * @Param []
     * @return java.awt.image.BufferedImage
     **/
    public BufferedImage getImage() {
        return this.image;
    }

    /**
     * @Author zflu
     * @Description 获得验证码
     * @Date 2018/7/8 14:27
     * @Param []
     * @return java.lang.String
     **/
    public String getString() {
        return this.str;
    }

    /**
    * @Author zflu
    * @Description 初始化图片
    * @Date 2018/7/8 14:28
    * @Param []
    * @return void
    **/
    private void init() {
        // 在内存中创建图象
        int width = 85, height = 20;
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        // 获取图形上下文
        Graphics g = image.getGraphics();
        // 生成随机类
        Random random = new Random();
        // 设定背景色
        g.setColor(getRandColor(200, 250));
        g.fillRect(0, 0, width, height);
        // 设定字体
        g.setFont(new Font("Times New Roman", Font.PLAIN, 18));
        // 随机产生155条干扰线，使图象中的认证码不易被其它程序探测到
        g.setColor(getRandColor(160, 200));
        for (int i = 0; i < 155; i++) {
            int x = random.nextInt(width);
            int y = random.nextInt(height);
            int xl = random.nextInt(12);
            int yl = random.nextInt(12);
            g.drawLine(x, y, x + xl, y + yl);
        }
        // 取随机产生的认证码(4位数字)
        String sRand = "";
        for (int i = 0; i < 4; i++) {
            String rand = String.valueOf(Contants.code[random.nextInt(Contants.code.length)]);
            sRand += rand;
            // 将认证码显示到图象中
            g.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random.nextInt(110)));
            // 调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成
            g.drawString(rand, 13 * i + 6, 16);
        }
        // 赋值验证码
        this.str = sRand;

        // 图象生效
        g.dispose();

        this.image = image;
    }

    private Color getRandColor(int fc, int bc) {
        Random random = new Random();
        if (fc > 255){
            fc = 255;
        }
        if (bc > 255){
            bc = 255;
        }
        int r = fc + random.nextInt(bc - fc);
        int g = fc + random.nextInt(bc - fc);
        int b = fc + random.nextInt(bc - fc);
        return new Color(r, g, b);
    }
}